A. Field of the Invention
The present invention relates to a mechanism for use with a vacuum packaging apparatus. More particularly, the invention is a combined cutting blade and heating bar for use in cutting and sealing vacuum packing bags, and in particular, oversized compressible content in vacuum packing bags.
B. Description of the Related Art
Manufacturers often desire to package their products in air-tight or shrinked wrapped bags. For example, a manufacturer may wish to seal a food product in an air-tight package to ensure its freshness or may wish to vacuum pack a compressible product in order to reduce the size of the packaging. Also, it is sometimes either expensive to package a product in a box or desirable to visibly display the product. In these cases, the manufacturer may shrink-wrap the product in a clear plastic bag. This type of packaging allows the consumer to see the product, protects the product during shipping and, in certain instances, when the content can be compressed through the vacuum packaging process, reduces the size of the package.
Currently, machinery is available for packaging products in air-tight bags. This machinery typically comprises a base member having an upstanding wall defining an internal cavity in which a bagged product may be placed. A lid is movable over the base, the lid having a perimeter sealing element for forming a seal against the top of the wall of the base.
A movable heated element is connected to the lid. The heated element can be extended downwardly against a portion of the base. Means are provided for evacuating the air from the cavity.
The prior teaches several ways in which to pull vacuum through the bag and seal the container. One such approach is to place the bag in the cavity of the base, such that the open end of the bag is oriented so that it extends across a portion of the base, with the free end also located in a slot within the cavity. Thus the entire bag is placed within the cavity.
Once the bag is placed in the cavity, the lid is lowered and sealed against the base. The cavity and thus the bag therein, is evacuated of air. The air leaving the bag through its open end located within the cavity. Evacuation of the air in the bag draws the bag tightly around the product and itself. The heated element is then heated and lowered against the bag. The heat element melts the bag distal of its open end, sealing it shut. Air is returned to the cavity, the lid opened, and the product is removed.
This packaging arrangement suffers the drawback that the entire bag must be located in the cavity in order to evacuate the air therein. When there is excess bag to wrap the product, the bag material is bunched around and often extends from the product. This bag material increases the total size of the package, and is visually unappealing. Furthermore, this type of machine is not well suited to package large items by reducing the size of the items by pulling a vacuum through the package. This system would tear the pouch completely loose during the initial vacuum draw down and disrupt the packaging cycle.
To overcome the drawback of bunching when excess baggage is used, other vacuum packaging machines were designed to allow a user to leave the end of the bag outside of the chamber during air evacuation. When using this type of device, the user places the product in the bag and pulls the end of the bag outside of the base. The user pulls the bag firmly outwardly, pulling the bag tightly around the product in the chamber, leaving only the amount of bag necessary to wrap the product around the product.
The user then lowers the lid, tightly holding the bag in place, preventing it from slipping back down into the chamber around the product. The vacuum packaging machine includes a segmented cutting blade and heating element for use with the vacuum packaging device, which may be connected to a single actuating device, or each connected to their own actuating devise. In either case, when the lid is closed, the segmented cutting blade, which extends almost entire across the width of the first vacuum package machine, cuts segmented portions of the bag located inside of the chamber, as illustrated by FIG. 2 (Prior Art). The cuts are segmented so that the bag, when cut, does not slip back down into the chamber around the product, but so that the excess bag can be easily removed from the bag containing the product after the bag is sealed.
Once the bag is cut, the air in the chamber and in the bag located inside of the chamber is evacuated, the air escaping from the bag through the cuts. After the vacuum is pulled through the chamber, the heating element is lowered, melting the bag distal of the cut made in the bag and sealing it shut, as illustrated by FIG. 2 (Prior Art). The product is then removed from the container and the excess bag on the free end away from the seal is then removed.
Like the vacuum packaging machine having the entire bag located in the cavity, the machines allowing for the open end of the bag located outside the chamber, also suffer the difficulty of packaging large condensable items by pulling a vacuum through the package and thereby causing the packaging to condense the product in the package. For example, such items subject to reduction though vacuum packaging are clothing, outdoor wear, sleeping bags and other flexible, resilient compressible materials. Under high vacuum packaging, such fabric derived products will compress in size by up to 30% of their original volume.
The prior art vacuum packaging machines are not currently equipped to accommodate these type of compressible products. The prior art vacuum packaging machines, as discussed above, pulls a small vacuum to hold the chamber closed when the lid is initially shut and to create a seal between the lid and the base. In the case of packaging large pouches with sleeping bags or other like large clothing articles, this system would tear the pouch completely loose during the initial lid vacuum draw down and disrupt the packaging cycle.